1. Technical Field
The invention relates generally to Internet based centralized user privacy preferences management technology. More particularly, this invention relates to a system and method for user privacy preferences roaming among clients and Web services and privacy enforcement at Web services base on the requesters' privacy policies.
2. Description of the Prior Art
The Platform for Privacy Preferences Project (P3P), developed by the World Wide Web Consortium, is emerging as an industry standard providing a simple, automated way for users to gain more control over the use of personal information on Web sites they visit. P3P has been designed to promote privacy and trust on the Web by enabling Web services to disclose their information practices, and enabling Web users to make informed decisions about the collection and use of their personal information.
P3P is an important building block of a new privacy protection concept that increasingly focuses on transparency and market-economy elements. At its most basic level, P3P is a standardized set of multiple-choice questions, covering all the major aspects of a Web site's privacy policies. Taken together, they present a clear snapshot of how a site handles personal information about its users. P3P-enabled Web sites make this information available in a standard, machine-readable format. P3P-enabled browsers can read this snapshot automatically and compare it to the consumer's own set of privacy preferences. P3P enhances user control by putting privacy policies where users can find them, in a form users can understand, and, most importantly, enables users to act on what they see.
P3P allows users' Web browsers to understand Web sites' privacy practices automatically. Privacy policies are embedded in the code of a Web site. Browsers read the policy, and then, automatically provide certain information to specific Web sites based on the preferences set by the users and stored as a User Preference file on the user's computer. The User Preference file specifies what kinds of practices the user will accept, what kinds should be rejected, and what kinds should cause the program to prompt the user to decide how to respond.
The P3P specification provides syntax for specifying privacy policies, privacy preferences (APPEL) and a protocol for exchanging information between the Web site and user agent. Sophisticated preferences may be difficult for end-users to specify, even through well-crafted user interfaces. An organization can create a set of recommended preferences for users. Users who trust that organization can install a pre-defined rule set rather than specifying a new set from scratch. It will be easy to change the active rule set on a single computer, or to carry a rule set to a new computer.
Categories are vital to making P3P user agents easier to implement and use; they allow users to express more generalized preferences and rules over the exchange of their data. Categories are often included when defining a new element or when referring to data that the user is prompted to type in, as opposed to data stored in the user data repository. Categories themselves are not data-elements, but are a more generalized description of a set of single data-elements, which belong to this category.
Using the policy-reference-file, by defining realms in the header of the answer, servers can not only define different policies on the same server, but also a same policy for different servers. To define different policies on the same server can be useful, when there are pages, that can be browsed and where the service does not collect any data and other pages for shopping or feedback, where data is collected and a certain purpose would be addressed.
The first major commercial user agent implementation of P3P is Microsoft's Internet Explorer 6 Web browser released in the summer of 2001, which is focused on cookie blocking. Other P3P software (for example, the AT&T Privacy Bird) uses the full P3P policy more extensively than it is used in IE6. IBM released a P3P policy editor tool that Web sites can use to create their P3P policies. This tool has been used by many of the Web sites that adopted P3P.
After all, only few user agents now support P3P privacy preferences. Even these user agents have implemented only partial solutions such as merely dealing with cookies. These browser based P3P privacy preferences are only applicable when the user is using that particular browser. In addition, because Web services design their access control languages, such as XACML (an XML specification for expressing policies for information access over the Internet) from OASIS and HSDL from Microsoft's .NET MyServices, Web users are required to manage multiple sets of privacy preferences, each specified in different languages or tools. Further, none of the Web services enforces user's privacy preferences according to requester's P3P policies.
Therefore, there is a need for a mechanism according to which a user has only a single set of privacy preferences and this single privacy preferences and any of its modifications are propagated among Web browsers and Web services. What is further needed is that the user's privacy preferences are enforced at Web services based on the requester's privacy policies.